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Harma Valves / 6072A/12AY7-HARMA STR
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All prices contained on this page are exclusive of VAT. This is currently charged at 20% and is payable by the UK only.
All prices contained on this page are exclusive of VAT. This is currently charged at 20% and is payable by the UK only.
Harma valves consist of a selected range of valves that are chosen after meeting stringent standards for sound quality and reliability. These valves are sourced from current production as well as some of the finest Nos valves available. Unlike our competitors no Harma valves, past or present has been made in China. Harma valves represent the finest available items of their type available.
Harma valves are tested using a range of custom designed and built test rigs which are unique to Watford valves.These unique tests are not offered by any other valve supplier in the world.
All Harma pre amp valves undergo the drive rating system; the valve undergoes a series of through tests under full operational conditions. This involves a controlled burn in process to ensure perfect stability and correct ageing. A shock and vibration test, microphoney, hum, and a balance and symmetry test.
All Harma output valves undergo our own unique real world burst testing. No other supplier tests valves this way. The burst testing process involves a series of varying timed electrical signal bursts. This runs the valves under the same stress conditions that they will meet in your amplifier especially when overdriven. All out put valves are then dual matched by us on anode current and gain. This will ensure that you get the best selected valves available anywhere in the world.
The Harma 12AY7 STR plate construction is based on the famous frame grid plate design that was pioneered in Germany by Telefunken.Harma valves are tested using a range of custom designed and built test rigs which are unique to Watford valves.These unique tests are not offered by any other valve supplier in the world.
All Harma pre amp valves undergo the drive rating system; the valve undergoes a series of through tests under full operational conditions. This involves a controlled burn in process to ensure perfect stability and correct ageing. A shock and vibration test, microphoney, hum, and a balance and symmetry test.
All Harma output valves undergo our own unique real world burst testing. No other supplier tests valves this way. The burst testing process involves a series of varying timed electrical signal bursts. This runs the valves under the same stress conditions that they will meet in your amplifier especially when overdriven. All out put valves are then dual matched by us on anode current and gain. This will ensure that you get the best selected valves available anywhere in the world.
Though the Harma is not a frame grid valve by using this plate structure it has a number of real advantages. The internally rugged construction with thick mica supports provides reduced microphonics and better isolation from vibration. This is particularly useful in combo applications. When put in the first gain position it will lower the gain of a pre amp circuit by around 50-60%.
Sonically valve is very well balanced with nice even bass which has plenty of depth and a clear and articulate top end.
This is one of the most neutral sounding of all the current production 12AY7 types. So is ideal to recreate the vintage sound of the early 1950's Fender amplifiers. This is also a great option for harp players wishing to drop the gain of their amplifier in the V1 position to prevent feedback.
All Harma preamp valves are Dynamically Drive tested under real working condition have passed the following tests:
Gain (db) Drive Tested)
Transconductance (gm) Drive Tested
Output Drive Tested
Noise 1 (signal to noise)
Noise 2 (Aural)
Microphonics Test 1(Ambient)
Microphonic Test 2 (Shock)
Cathode Test
Grid Leakage Test
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